Stone-cutting machine



(No Model.)

W. L. SAUNDERS.

STONE CUTTING MACHINE. No. 320,293. Patented June 16, 1885.

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XVILLIAM L. SAUNDERS, OF JERSEY CITY, NEXV JERSEY.

STONE-CUTTING MACHINE.

SPECIFICATION forming part of Letters Patent No. 320,293, dated June 16, 1885.

Application filed January 8, 1885. (No model.)

To (LZZ whom-it may concern:

Be it known that I, \VILLLUI L. SAUNDERS, a citizen of the United States, residing at Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in StoneOutting Machines, of which the following is a specification, reference being had to the accompanying drawing.

The object of my invention is to provide means for regulating the force of the blows dealt upon the stone by the cutters of a stonecutting machine and to preserve an elastic cushion under the piston, which will cause it to rebound after a stroke and prevent the sticking of the cutters in the channel, and also enable the machine to continue its lateral feed over irregular surfaces without sticking and damaging the lower or front cylinder-head.

In channeling stone where a gang of drills I is operated reciprocatively by the piston of a steam or air engine (the drills being fixed to the piston of said engine) it is of great importance to be able to govern the force of the low. In channeling granite a harder blow is required than when channeling sandstone. In the latter case a hard blow would drive the cutters so deeply into the stone as to prevent their being released without great strain upon the parts of the machine. Furthermore, in reaming out the cut with drills having bits of enlarged diameter, it is desirable to work them in the out without striking the bottom until the side walls are reamed out to the desired gage. .Vith a direct-acting channeling-machine exhausting on both the up and the down strokes of the piston this would not be feasible, as the force of the blow on the downstroke would be so great, on account of the exhausting of the steam underneath the piston, that the drills would be wedged into the out.

In order to operate successfully over an irregular surface with a channeling-machine carried on a horizontral track or support, I

\ provide a permanent cushion of live steam or air under or in front of the piston, and in starting a cut over an irregular surface where the stone is raised and depressed at different places with a machine having an elastic cushion under the piston the lateral feed of the carriage upon the track may be continued without regard to the character of the surface,

while the drills will cut on the high places, and while being carried over the depressions by the feed mechanism will cushion on the steam on the front of the cylinder. I am thus enabled to continue the reciprocative motion of the piston and drills and the horizontal motion of the carriage upon the track without attention or adjustment, and without the danger of the piston striking the front head of its cylinder.

The accompanying drawing is an elevation, partly in section, of the engine of a stone-cutting machine embodying my improvements.

Similar letters denote like parts.

A is a steam or air cylinder. B is the piston, and G the steam-chest, containing an ordinary slide-valve, O. The cylinder A differs from an ordinary engine-cylinder, in that it contains no lower steam-port connected with the valve, the steam being admitted underneath the piston through the passage I controlled by a throttle-valve, T. The throttle valve U controls the steam which passes through the Valve 0, steam being admitted from the source of supply through the hose II. Now, it is evident that with throttlesTand U both open there will be a constant pressure of live steam underneath the piston in the lower portion of the cylinder, the upper portion of the cylinder, forming the chamber J, being alternately filled with steam and exhausted through the steam and exhaust pipes J J while the lower chamber, L, contains a constant pressure of live steam. \Vith steam in both J and L the piston will be driven down by the excess of pressure at J, the difference of pressure being caused by the difference of area, the area at J being greater than that at L in proportion to the diameter of the pistonrod It. If we have thirteen square inches area at J, there will be thirteen square inches at L, less the square inches of area of the piston-rod B. This will give the piston a down ward stroke with steam in both upper and lower chambers. The downward stroke is furthermore assisted by the weight of the piston, cross-head, and drills. The throttles U and T serve to control the steam in both the upper and lower cylinder-chambers. If it is desired to strike a hard blow, the throttle T is partly closed, thus wire-drawing the steam, and with throttle U wide open there will be an excess ICO of pressure at J, thus causing the piston to descend with greater force than if '1 were wide open. On the contrary, with '1 wide open and U partly closed the conditions will be reversed and the piston will strike a light blow, cushioning early in its stroke. With these attachments it is evident the piston is in positive control of the runner. With throttle U closed, by opening throttleT the piston may be thrown to the upper end of the cylinder and held there, thus enabling the carriage to be moved along its track without the dragging of the drills in the cut.

Having described my invention,what I claim 1S- 1. In a rock-drilling machine, a steam-cylinder provided with steam and exhaust ports at one end and having a steam-inlet direct from the source of supply at its opposite end, and means, substantially as described, for increasing or diminishing the pressure on that portion of the cylinder constantly supplied with live steam, as set forth.

2. The combination, with a cylinder, A, having the steam-port J, and exhaust-port J, and suitable valve therefor, and the throttle U, of the piston B, piston-rod R, to which the tools are attached, and the auxiliary steampipe H to the lower portion of the, cylinder, with throttle T, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM L. SAUNDERS.

Witnesses:

JOHN D. MILLER, JOHN CUYAT. 

